OBJECTIVES: I. Compare the long-term survival of patients with chemotherapy-naive stage II or III multiple myeloma treated with standard melphalan and prednisone with or without adjuvant Wobe-Mugos E. II. Compare the effect of these two regimens on the reduction of the side effects from chemotherapy in these patients, using 2 quality of life questionnaires. III. Compare the effect of these two regimens on tumor response rate and new metastasis development in these patients.